St. Patrick's Day is celebrated on March 17, the saint's religious feast day and the anniversary of his death in the fifth century. The Irish have observed this day as a religious holiday for over 1,000 years. On St. Patrick's Day, which falls during the Christian season of Lent, Irish families would traditionally attend church in the morning and celebrate in the afternoon. Lenten prohibitions against the consumption of meat were waived and people would dance, drink and feast--on the traditional meal of Irish bacon and cabbage.

The Chicago River on St. Patrick's Day

As Irish immigrants spread out over the United States, other cities developed their own traditions. One of these is Chicago’s annual dyeing of the Chicago River green. The practice started in 1962, when city pollution-control workers used dyes to trace illegal sewage discharges and realized that the green dye might provide a unique way to celebrate the holiday. That year, they released 100 pounds of green vegetable dye into the river--enough to keep it green for a week! Today, in order to minimize environmental damage, only 40 pounds of dye are used, and the river turns green for only several hours.

Although Chicago historians claim their city's idea for a river of green was original, some natives of Savannah,Georgia (whose St. Patrick's Day parade, the oldest in the nation, dates back to 1813) believe the idea originated in their town. They point out that, in 1961, a hotel restaurant manager named Tom Woolley convinced city officials to dye Savannah's river green. The experiment didn't exactly work as planned, and the water only took on a slight greenish hue. Savannah never attempted to dye its river again, but Woolley maintains (though others refute the claim) that he personally suggested the idea to Chicago's Mayor Richard J. Daley.